Metal strips of this type, ranging in thickness from a few microns to about one millimeter, have heretofore been joined together by adhesively interconnecting their extremities which could then be cut off after treatment. When the treatment involves passage through a long oven or furnace, as for the purpose of drying a varnish or other coating previously applied to the strips, most adhesives--except for some rather expensive ones--cannot withstand the high temperatures so that the oven must be temporarily cooled down until the interconnected extremities have gone through. Such a procedure is highly uneconomical since it wastes thermal energy and also leaves substantial strip portions incompletely treated.